Image pickup device

Abstract

An image pickup device includes pixels, each including a photoelectric conversion unit and a transfer unit. The photoelectric conversion unit includes a first-conductivity-type first semiconductor region and a second-conductivity-type second semiconductor region. A second-conductivity-type third semiconductor region is formed on at least a part of a gap between a photoelectric conversion unit of a first pixel and a photoelectric conversion unit of a second pixel adjacent to the first pixel. A first-conductivity-type fourth semiconductor region having an impurity concentration higher than an impurity concentration of the first semiconductor region is formed between the photoelectric conversion unit and the third semiconductor region. A first-conductivity-type fifth semiconductor region having an impurity concentration higher than the first semiconductor region is arranged between the photoelectric conversion unit and the third semiconductor region and is arranged deeper than fourth semiconductor region.

What is claimed is: 
     
       1. A solid-state imaging device of a pixel amplifying type, comprising a plurality of pixels, wherein each pixel includes:
 a photoelectric conversion unit including a first semiconductor region of a first conductivity type and a second semiconductor region of a second conductivity type opposite to the first conductivity type; and 
 an amplifying transistor of the first conductivity type, 
 wherein the solid-state imaging device further comprises: 
 an element isolation region configured to electrically isolate the first semiconductor region from a peripheral element; 
 a third semiconductor region of the second conductivity type arranged along a lower surface of the element isolation region; and 
 a fourth semiconductor region of the second conductivity type arranged so as to partially overlap with the third semiconductor region in a planar view, wherein 
 the third semiconductor region is arranged so as not to overlap with a source or a drain of the amplifying transistor in the planar view, and 
 the fourth semiconductor region is arranged so as to partially overlap with the source or the drain of the amplifying transistor in the planar view. 
 
     
     
       2. The solid-state imaging device according to  claim 1 , wherein
 the third semiconductor region extends to a side portion of the element isolation region at a side of the photoelectric conversion unit. 
 
     
     
       3. The solid-state imaging device according to  claim 1 , wherein
 the second semiconductor region includes a plurality of semiconductor regions of the second conductivity type respectively arranged at depths different from each other. 
 
     
     
       4. The solid-state imaging device according to  claim 3 , wherein
 the plurality of semiconductor regions of the second conductivity type are formed respectively by ion implantations of which ion implantation energies are different from each other. 
 
     
     
       5. The solid-state imaging device according to  claim 1 , wherein
 the second semiconductor region has a little grade well structure. 
 
     
     
       6. The solid-state imaging device according to  claim 1 , further comprising:
 a fifth semiconductor region of the second conductivity type arranged above the first semiconductor region, wherein 
 the third semiconductor region and the fifth semiconductor region are arranged continuously from each other. 
 
     
     
       7. The solid-state imaging device according to  claim 1 , wherein
 the second semiconductor region is arranged between the source or the drain of the amplifying transistor and the fourth semiconductor region. 
 
     
     
       8. The solid-state imaging device according to  claim 1 , further comprising:
 a floating diffusion region to which a carrier is transferred from the photoelectric conversion unit, wherein 
 the fourth semiconductor region is arranged to surround the first semiconductor region and the floating diffusion region. 
 
     
     
       9. The solid-state imaging device according to  claim 8 , wherein
 the floating diffusion region is supplied with a fixed voltage during an accumulation period of the photoelectric conversion unit. 
 
     
     
       10. The solid-state imaging device according to  claim 1 , wherein
 the second and fourth semiconductor regions are formed respectively by ion implantations of which ion implantation energies are different from each other.